Preservative



Patented Feb. 6, 1934 PATENT OFFICE 1,946,057 PRESERVATIVE Edgar c. Britton and Lindley E. Mills, Midland, Mich., assignors to The Dow Chemical Com-- pany, Michigan Midland, Mich.,

a corporation of No Drawing. Application October 26, 1931 Serial No. 571,282

12 Claims.

The present invention concerns a new preservative and fungicide, comprising a polychlorinated phenol or a salt thereof, such preservative and fungicide being suitable for the treatment of articles (e. g. glue, etc.) subject to attack by fungi or insects, where such polychloro-phenolic compounds do not lend objectionable characteristics to the material so treated.

It is general practice to incorporate small quantities of phenolic substances such as betanaphthol, thymol, moldol (i. e. ortho-chlorometa-cresol) etc., with glue in order to prevent mold growth and general putrefaction in the same. The preservatives mentioned display a pronounced action in preventing mold growth and putrefaction, but their use in quantity sufficient to prevent deterioration of glue is costly and their presence in such quantity is sometimes objectionable.

We have now found that polychloro-phenols are generally superior to the above mentioned preservatives and may be used successfully to prevent mold growth and putrefaction in glue. Our new preservative is particularly advantageous in that polychloro-phenols may be prepared from chlorinated benzene at low cost, and in that relatively small quantities of certain polychloro-phenols are suflicient to prevent completely mold growth in glue. For instance, we 0 have found that a 30 per cent glue solution containing 0.05 per cent of 2.4.5-trichloro-phenol.

based on the weight of dry glue used, was free of mold after being inoculated with a fresh mold growth and being allowed to stand at a temperature of 25 C. during a period of six months.

A similar glue solution, containing 0.05 per cent of beta-naphthol as a preservative in place of the 2.4.5-trichloro-phenol mentioned above, was found to be molded upon standing at a temperature of 25 C. for only two days after inoculation with mold growth. The present invention, then, consists in a new preservative and fungicide comprising polychloro-phenol and in a method of treating various substances, e. g.

' glue, etc., with the same, such preservative and method being hereinafter fully described and particularly pointed out in the claims.

Our new preservative may be employed in various forms, e. g. as the free phenolic compound in powdered or liquid form or as a solution of the free polychloro-compound in an organic solvent. The particular form in which our preservative and fungicide should be used is dependent, of course, upon the kind and nature of material to be treated with the same but for general purposes it ispreferably employed as an aqueous solution of a water soluble salt of a polychloro-phenol, the alkali and alkaline earth salts of such compound being suitable for the purpose mentioned. When, however, a .polychloro-phenol is to be employed as a fungicide for the treatment of plants, said polychlorophenol may be applied as a solution of either the free phenolic compound or of its salts, or such fungicide may be applied in the form of a 55 dust comprising either the phenolic compound or any metal salt thereof, e. g. the copper salt.

The following description and accompanying table of examples set forth in detail several of the various modes of employing the principle of our invention, it being understood, however, that such description and examples are purely illustrative and are not to be construed as a limitation on the invention. For the sake of comparison, several commonly used preservatives have been tested as glue preservatives and the results from such tests listed in the table along with results obtained from similar tests using various polychloro-phenols as preservatives.

The utility of various phenolic compounds as glue preservatives was tested in the following way:The particular preservative to be tested was dissolved in its chemical equivalent of a sodium hydroxide solution to form a resultant solution containing 5 per cent of the phenolic compound (not 5 per cent of the sodium salt of said compound). Each glue sample was contained in a 250 cubic centimeter Erlenmeyer flask and consisted of 66.7 grams of a 30 per cent glue solution, based on the weight of dry glue used in its 9 preparation. To a freshly prepared glue sample, while still liquid, was added the desired amount of the above mentioned preservative solution. The glue was well mixed and then inoculated by dropping a small portion of fresh, well developed mold (from molded blue) upon its surface. The sample was then maintained at a temperature of 25 C. and the progress of mold growth recorded daily. In the table the term percen shall be understood to mean percent of preservative in the sample, based on the weight of dry glue used in preparing said sample. I In the table given below v are recorded results obtained from such tests,v the following system being used in tabulating such results:

+ represents presence of mold in the glue.

represents no mold growth present.

0 represents mold confined to portion of glue seeded.

R represents new mold seed added to the glue sample.

Table Time in days after inoculation with mold Preservative None Bets-naphtha].

I l l In the above table it will be noted that polychloro-phenols offer complete preservative action toward mold growth at a lower concentration of the preservative used than do any of the other preservatives tested. In addition to preventing the growth of mold in glue, our new preservative also tends to prevent general putrefaction of the same. For instance, a glue sample, treated with 2.4.5-trichloro-phenol so as to form a glue solution containing 0.05 per cent of the phenolic compound gave no evidence of putrefaction after standing at a temperature of 25 C. for a period of six months. A similar glue solution containing no preservative developed an unpleasant odor after standing at the above mentioned temperature for a period of 1 to 3 days and another glue sample containing 0.05 per cent of beta-naphthol developed putrefaction after standing under conditions similar to those mentioned for a period of 3 to 5 days.

Other modes of applying the principle of our invention may be employed instead of those explained, change being made as regards the materials employed, provided the ingredients stated by any of the following claims or the equivalent of such stated ingredients be employed.

We therefore particularly point out and distinctly claim as our invention:-

llllllllllllll'l-ll+ll+- 4. As a composition of matter, glue containing 2.3.4.6-tetrachloro-phenol.

5. As a composition of matter, glue containing a salt of 2.3.4.6-tetrachloro-phenol with a metal selected from the class consisting of alkali and alkaline-earth metals.

6. As a composition of matter, glue containing a compound selected from the class consisting of trichloro-phenols and alkali and alkaline-earth metal salts thereof.

7. As a composition of matter. glue containing a compound selected from the class consisting of 2.4.5-trichloro-phenol and alkali and alkalineearth metal salts thereof.

8. As a composition of matter, glue containing 2.4.5-trichloro-phenol.

9. As a composition of matter, glue containing an alkali metal salt of 2.4.5-trichloro-phenol.

10. As a composition of matter, glue containing a compound selected from the class consisting of 2.4.6-trichloro-phenol and alkali and alkalineearth metal salts thereof.

11. As a composition of matter, glue containing 2.4.6-trichloro-pheno1.

12. As a composition of matter, glue containing an alkali metal salt of 2.4.6-trichloro-phenol.

EDGAR C. BRITTON. LINDLEY E. MILLS. 

